1. Field of the Invention
The present invention relates to a modular electronic assembly which is inserted in a casing, and more particularly to an improved battery holder which will allow the modular electronic assembly to operate while it is outside the casing.
2. Description of the Prior Art
Presently, all of the modular electronic assemblies are inserted into metal casings which serve not only as battery holders, but also as conduction paths for the electronic circuits in the modular electronic assemblies. Each modular electronic assembly includes a pair of 11/2 volts, one cell batteries, a substrate with a printed circuit placed thereon, an electrooptical display which is mounted on the substrate and an integrated circuit chip which is mounted on the substrate and electrically connected to the electrooptical display and the pair of batteries through the printed circuit. U.S. Pat. No. 3,838,568, entitled Electronic Watch Movement Mounting and Connection, issued to Rudolf F. Zurcher and I. Benjamin Merles on Oct. 1, 1974 sets forth a description of a modular electronic assembly which is inserted in a metal casing. The modular electronic assembly includes a substrate that is mounted on a battery holder in such a manner that it may move in a lateral direction across the top surface of the battery holder. A set of springs restrains the lateral movement of the substrate across the top surface of the battery holder. At least one of the springs connects itself to the integrated circuit chip and to the metal casing when when a pushbutton switch is depressed so that an electrical signal can travel along a conduction path through the metal casing from one of the batteries. It is therefore essential that the casing be metallic in order for this electronic modular assembly to operate.
The above described modular electronic assembly is inoperable when it is outside the metal casing because there is no conduction path through which the electrical signal can travel from the battery to the integrated circuit chip. Generally the metal casing includes a ring having a front edge adapted to receive a viewing element, such as a watch crystal or a watch glass, and to hold that viewing element in place, and a back element adapted so that it is mechanically coupled to the ring adjacent the back edge thereof. The modular electronic assembly is placed in the ring between the viewing element and the back element, which are both secured at the front edge and the back edge of the ring, respectively.
U.S. Pat. No. 3,597,913, entitled Battery-Carrying Means For Electric or Electronic Time Piece, issued to Motoyuki Fujimori Suwa-shi on Aug. 10, 1971, teaches a battery-carrying device for an electronic assembly wherein an elastic contact projects from a cover providing access to a battery receiving device in the electronic assembly. The contact is positioned so that the battery is out of contact with the cover when it is inserted in the wrong direction. This arrangement prevents a short-circuit of the battery. The cover and the elastic contact are mounted so that they press against the outer periphery of the battery and allow an electrical current to flow to the electronic circuitry of the electronic assembly.
An insulating device is fastened to the central portion of the inner surface of the cover. The insulating device acts to prevent short-circuiting of the batteries. In the battery carrying device it should be noted that it again requires the cover to be metallic in order to operate the electronic circuit.
Another solid state wristwatch is the subject of U.S. Pat. No. 3,759,031, entitled Modular Solid State Wristwatch, issued to Robert W. McCullough and Cleon W. Hougendobler on Sept. 18, 1973. The patent discloses a solid state wristwatch that includes a substrate having a printed circuit on its back surface and having an integrated circuit chip mounted on its front surface and that is supplied with electrical power by a pair of batteries. The wristwatch also includes a modular frame on which the substrate rests and which contains the pair of batteries. The modular frame is formed from an impact-resistent, one-piece, injection molded plastic material and is disc-shaped. The modular frame has a circular rim and a solid central section with an enlarged portion having cavities, adapted to receive 11/2 volts, one cell batteries. At the bottom of each cavity is a through hole which is adapted to receive an electrically conductive metallic spring for establishing an electrical connection between the pair of batteries and an electrical connection to a metal casing in which the substrate and the modular frame are placed. It is again essential that the casing be metallic in order for the solid state wristwatch to operate because the casing provides a conduction path for an electrical signal from the batteries to the integrated circuit chip.
The substrate of the above described wristwatch is secured to the modular frame by a silicone rubber adhesive which not only holds the substrate in place, but also provides shock absorption for the integrated circuit chip. The application of the silicone rubber adhesive requires an additional step in assembling the wristwatch and makes the resulting modular electronic assembly formed from the modular frame and the substrate non-uniform in size. The non-uniformity in size is only a problem when the module is placed in a relatively thin casing.